COMMENTARY

Reply to Stan Becker, “Has the World ReallySurvived the Population Bomb? (Commentaryon “How the World Survived the PopulationBomb: Lessons from 50 Years of ExtraordinaryDemographic History”)”

David Lam

Published online: 17 October 2013# Population Association of America 2013

My 2011 PAA presidential address (Lam 2011), the focus of Stan Becker’s comment,presented an optimistic perspective on how the world fared during the last 50 years ofdemographic history. An online commenter of a related op-ed column I wrote for theLos Angeles Times called me “Professor Happy Talk.” In my opinion, this optimisticview is entirely warranted. Although the last 50 years saw what was by far the fastestpopulation growth the world has ever seen, it seems quite certain that this period alsosaw the largest improvements in the human condition of any 50 years in history. Thisremarkable achievement should surely make us optimistic about our ability to addressthe many complex challenges we will face in the next 50 years.

Although I am optimistic about the future of humanity, I am not as optimistic asJulian Simon’s statement that “every trend in material welfare has been improving—andpromises to do so, indefinitely” (Simon 1996). That position ignores serious setbacks,such as a decrease in life expectancy in some African countries resulting fromHIV/AIDS as well as many kinds of environmental degradation that are effectivelylosses in wealth. In my address, I discussed some areas in which the record of the last 50years is less positive, including disappointing progress in reducing poverty in Africa andenvironmental problems, such as global warming. I concede, however, that these topicsreceived only limited discussion. I deliberately focused on the positive because I believethat the positive trends dominate the negative and because the positive trends are oftenoverlooked. I’m pleased that Becker has continued the discussion and given moreattention to some of these important areas in which we face real challenges.

Becker notes areas in which the world does not look as rosy as the world I describedin my address. Among these are depletion of aquifers, depletion of oil, global warming,

Demography (2013) 50:2183–2186DOI 10.1007/s13524-013-0249-6

The online version of the original article can be found under doi: 10.1007/s13524-013-0236-y

D. Lam (*)Department of Economics and Population Studies Center, University of Michigan, 426 ThompsonStreet, Ann Arbor, MI 48106, USAe-mail: davidl@umich.edu

and species loss. One possible response to these points is to counter with a list ofadditional indicators that suggest the world has been improving. Becker could respondwithmore indicators that have showed deterioration.We could continue this “half emptyor half full” debate through many issues of Demography. The reality, of course, is thatsome things are getting better and some things are getting worse. I think the good faroutweighs the bad. Rather than adding more items to my “half full” list, I will focus onsome “big picture” questions raised in Becker’s comment.

Humans Versus Nonhumans

Becker argues that the “world” I referred to was only the world of humans, neglectingnonhuman species and the natural environment more generally. For the most part, Iconcede this point. My perspective was on how humans were affected by an unprece-dented explosion in the number of humans. That requires understanding why theexplosion took place in the first place and why the explosion has, for the most part,come to an end. Whether humans are more worthy of consideration than other species isa philosophical and ethical issue on which I have no particular expertise. It seems worthpondering the following, however: suppose someone predicted in 1960 that the worldwould add 4 billion people in the next 50 years (by far the fastest increase in humanhistory), that after 50 years the human population would be considerably better off thanit was in 1960, and that the main focus of debate would be on the consequences of thehuman population explosion for nonhumans. Surely that would have been considered awildly optimistic scenario in 1960, given concerns at the time about mass starvation andimpoverishment. Yet this is, for the most part, exactly where we find ourselves. On awide range of measures—food consumption, income, infant mortality, life expectancy,poverty, education, and many others—the average human in 2013 is much better offthan the average human in 1960, in spite of the fact that there are 4 billion more of ustoday. Although it is important to consider what damage may have been done to theenvironment and to nonhumans in order to accomplish this, it is nonetheless an amazingaccomplishment that is worthy of recognition.

This is not necessarily to concede Becker’s argument that nonhumans and the envi-ronment have deteriorated in the last 50 years. In this dimension, I agree with him on somepoints and disagree on others. There are important lessons to be drawn from distinguishingthe areas in which there has been deterioration and the areas in which there has not.

Nonsustainable Use of Resources

One of Becker’s key points is that feeding an extra 4 billion people has required extensiveuse of nonrenewable resources, such as fossil fuels and phosphorus, along with massiveuse of water that has depleted aquifers. I share his concern about aquifers, although I amless concerned about nonrenewable resources. Aquifers are in trouble for the same reasonthat we have air pollution and overfishing of the oceans: a lack of property rights makes itdifficult for market forces to encourage careful use of resources.We do occasionally makeprogress on managing aquifers, and their management is arguably more amenable topolicy solutions than other externality problems, such as global warming. The

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consequences of aquifer depletion are felt very close to home by those affected, and thereare potentially solutions involving creative resource management. The Giordano (2009)paper Becker cites, which describes many challenges affecting groundwater around theworld, also discusses some of the successful efforts to manage aquifers. The successes areadmittedly few, however, and I agree with Becker that aquifer depletion is an importantchallenge that will require serious attention if we are going to feed another 3 billion peopleand continue to reduce poverty.

Although I agree with Becker’s concern about water, I am less concerned that we willrun out of oil or any other resource that has clear property rights and active markets.Predictions that we will soon experience “peak oil” are much disputed, with many energyeconomists pointing to enormous potential in unconventional petroleum reserves, even ifconventional reserves decline (Smith 2009). Some of these unconventional sources raisenew environmental concerns of their own, and these should not be minimized. But itseems unlikely that we will simply run out of oil, given the potential supply response ifprices rise. Indeed, the more important challenge is reducing oil consumption even as wehave large quantities available. Market forces are likely to keep us in petroleum productsfor a long time. Market forces in and of themselves will not lead to reduced carbonemissions, however, and that is arguably the more urgent challenge.

Becker also mentions deforestation and species loss. Both of these are importantissues. Much deforestation (a major contributor to greenhouse emissions and tospecies loss) is illegal, and its magnitude depends on the aggressiveness of localand national officials. Recent work by Burgess et al. (2012) shows that illegal loggingin Indonesia increases when there are more competing political jurisdictions in agiven area. This suggests that there is some hope for decreasing illegal logging bycreating an institutional environment in which local communities have increasedincentives to monitor local forests. The point is that it will take institutional change,not simply the end of population growth, to solve the problem.

Is there a strong link between the population growth of the last 50 years andproblems such as deforestation, species loss, depletion of aquifers, and globalwarming? To some, it may seem obvious that these problems would be less severeif world population were still 3 billion instead of 7 billion. As suggested by theNational Research Council’s (1986) report on population and development, however,as long as the underlying causes of these problems exist—incomplete property rightscombined with nonexistent or poorly enforced regulation—the problems will persist.Stopping population growth is unlikely to end aquifer depletion or deforestation, aslong as the fundamental externality issues have not been solved.

Valuing Future Generations

Becker concludes by arguing that children born in 2050 will look back and wish that wehad done more to preserve the world that was bequeathed to us. That may be true, but Isuspect they will also care about what kind of living standards we have created for themin a broader sense. How do we feel about the world that was passed on to us by previousgenerations? Most of us place great value on efforts at resource conservation, such asnational parks, wildlife preservation, and environmental success stories like the 1987Montreal Protocol that reduced chlorofluorocarbon emissions. But we also place

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great value on technological advances, such as electricity, automobiles, airplanes, andcomputers. Suppose we put James Watt’s 1776 steam engine to the test of sustainabledevelopment suggested by Becker: “development that meets the needs of the presentwithout compromising the ability of future generations to meet their own needs.”Would it have passed the test? Heavy use of the steam engine required the use of largeamounts of nonrenewable coal (which the engines helped extract), with no plan for asubstitute for the rapidly depleted coal. Would we future generations have been betteroff if Watt had decided to work on something else because the steam engine was nota sustainable technology? Would electricity have passed the test of a sustainabletechnology? Would we be better off if it had never been invented?

The question is, What practical guidance do we get from having a goal of sustainabledevelopment? Does it tell us whether the computer was a good invention? Does it helpan individual consumer decide whether to buy a computer or a television or a refriger-ator? It’s also important to recognize that most people do think a lot about futuregenerations in their everyday decision-making. Giving weight to future generations isnot something that requires a fundamental change of human thinking. Caring about thewelfare of our children and our grandchildren is as hard-wired in our brains as the desireto have children and grandchildren in the first place. This does not mean that wenecessarily give as much weight to them as they might wish we did. But parents andgrandparents everywhere devote enormous time and resources to improving the lives oftheir descendants. One of the important reasons that the average human is better offtoday than 50 years ago is that that parents worked hard to give their children a better lifethan they had—for example, by investing in their health and education; by migrating tocities and countries with better economic opportunities; and by building farms, business,and institutions that would make life better for the next generation.

I agree with Becker that the world (human and nonhuman) faces many challenges inthe coming decades. My claim that the world has survived the population bomb is not aclaim that it was easy or that we did not create new challenges along the way. My claimis simply that humans did something quite remarkable: adding 4 billion people to theworld while also improving most measures of human well-being. This required hardwork, ingenuity, and good institutions. We must now feed and house another 3 billionpeople by the end of this century, while addressing the kinds of environmental chal-lenges Becker points out. It will take more hard work and ingenuity, but the record of thelast 50 years gives us good reason to be optimistic that we can do it.

References

Burgess, R., Hansen, M., Olken, B. A., Potapov, P., & Sieber, S. (2012). The political economy ofdeforestation in the tropics. Quarterly Journal of Economics, 127, 1707–1754.

National Research Council (1986). Population growth and economic development: Policy questions.Washington, DC: National Academy Press.

Giordano, M. (2009). Global groundwater? Issues and solutions. Annual Review of Environment andResources, 34, 153–178.

Lam, D. (2011). How the world survived the population bomb: Lessons from 50 years of extraordinarydemographic history. Demography, 48, 1231–1262.

Simon, J. (1996). The ultimate resource 2. Princeton, NJ: Princeton University Press.Smith, J. L. (2009). World oil: Market or mayhem? Journal of Economic Perspectives, 23, 145–164.

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